serial console connections but not graphical consoles. This fixes the
graphical console machines. It leaves the initial promcons console
driver in place until a bit later in the boot sequence, delaying the
switch to the device drivers more appropriate for the machine's real
console setup. Note we still need the delayed make_dev() for promcons,
it does not have a proper bus interface so unlike other console drivers
it will not be found later during normal device discovery.
Tested by: sepotvin <at> videotron <dot> ca
Root cause explained by: grehan (-current)
Approved by: rwatson (mentor)
ea753400f0